Add to a drop down Menu?

Hi.. complete newbie, so please bear with me if my question is stupid!
I have the real estate theme installed. There is a ‘users’ page that we have. Id like to copy & modify this so it can be local businesses/attractions on another page.
The question I have, the drop down search bar at the top of the page currently has only two search terms in it ‘Username’ & ‘Email’ Is there a way of a) either changing these names so they say for example ‘restaurants’, adventure parks’ or b) adding to the list with other search term choices that we need?
Hope someone can help!